Re: Happy column adding (was RE: [HACKERS] Happycolumndropping)

Don Baccus wrote:
> 
> At 02:25 AM 1/26/00 +0200, Hannu Krosing wrote:
> 
> >multiple inheritance is tricky and _requires_ unique column ids maybe oids
> >from pg_attribute to be doable.
> 
> Having worked on a C++ compiler (one of the first, actually) I
> suspect that this might be one of the lesser problems associated
> with implementing a multiple inheritance scheme :)
>

I was aiming at a more loose way of doing multiple inheritance, something like
is used in python - you don't check too many things at compile time and
dynamically 
lookup them when needed.

for this the most_basic_column_oid scheme might work.

having unique indexes that span multiple tables would of course be tricky too, 
as would triggers and rules and ...

table a (oidA1, oidA2)
table b (oidB1, oidB2)
table c (oidC1) inherits(a,b)
alter table a drop column oidA2
alter table b add column oidB3
-->
table a - (oidA1,delA2)
table b - (oidB1,oidB2,oidB3)
table c - (oidA1,delA2,oidB1,oidB2,oidC1,oidB3)

seems the only sensible way for multiple inheritance to work with ADD/DROP
COLUMN 
is going with column oids for storage.

Hidden columns only would work for single inheritance. 

------------
Hannu